Motive

But I knew I just couldn't let this go. Girls were murdered for more than half a century, apparently by at least 5 different people, if Mo was right about the house changing hands every ten years after Mark Finch. What would make as many as four men go mad and follow in Finch's footsteps? I could kind of understand Finch, not that I condoned his actions, but he had lost his mother and it obviously drove him mad. But why would the other men carry on the tradition of murdering young blonde girls if they hadn't suffered that loss?